It is said that Solange, the 9th-century Frankish martyr, was beheaded by a local nobleman for rejecting his advances, but still managed to carry her own head to the local church, whereupon she collapsed and died.

The things some people will do for attention. Solange Knowles, presumably named after the saint (it's unlikely that mummy and daddy Knowles took it from Willy Kyrklund's Finnish novel) first came to my attention at the age of 14 when I saw her standing in, or rather dancing in, for her big sister Beyoncé after the latter had her leg in plaster and could complete a Destiny's Child concert only from the comfort of a high stool.

Now aged 26, she no longer needs to vie for anyone's attention. Especially in January, when the dearth of other significant London gigs makes her two nights in this Old Street basement the hottest ticket in town. The entire music industry and media seem to be present, as well as a scattering of celebrities. (I almost fall over Nicola Roberts from Girls Aloud on the way in.) I only wish they'd shut up: too many of the more restrained moments of Solange's set – and restraint is very much what she does – are drowned out by their incessant chatter about HMV, office politics and general Shoreditch tittle-tattle.

Working to her own agenda and her own pace (with five-year gaps between albums), Solange has proven her worth without having to flag up that box-office surname. Having parted ways with Interscope and signed with indie label Terrible, she's in a stronger position than ever to dictate the direction of her career. Not that it seems to have been a problem so far: her 2003 debut Solo Star may have been underwhelming and unremarkable, save for the Neptunes-produced Crush (tellingly, the only excerpt she performs tonight), but her 2008 return was an astonishingly individualistic, even groundbreaking record. Sol-Angel and the Hadley St Dreams was a stunning mix of the vintage and the avant-garde, featuring collaborations ranging from Motown legend Lamont Dozier to Scottish electro-ambient duo Boards of Canada. It arguably paved the way for the future-soul adventures of Janelle Monáe, and definitely prefigured some of Beyoncé's subsequent changes of direction.

But we must stop using the B‑word, because anyone with half a brain is here for what Solange does, not who she is (nor, indeed, who her sister is). And what she's doing, as of 2012‑2013, is working with Londoner Dev Hynes, aka Blood Orange (and, of course, Lightspeed Champion). The fruits of their collaboration so far amounts to the seven-track EP True, all of which is performed tonight, "Look Good with Trouble" sounding particularly sublime (even if lead track "Losing You" gets the biggest cheers).

Wearing a lurid superfly fleur-de-lys pattern trouser suit and an impressive afro (all the better for hiding an in-ear monitor), she enters to one of those new numbers, the shuddering "Some Things (Never Seem to Fucking Work)" and a rapturous reception, although the attention levels – that phrase again – dip badly when she tries anything too subtle (such as Selena cover "I Could Fall in Love"), and the hipsters start fiddling with their iPads.

Solange's charisma, unfortunately for a situation like this, is not the domineering kind. She can move (her occasional bursts into old school Jacko-meets-Temptations dancing are a joy), and she has an easy-going charm, but it'll take something more than that to silence these idiots.

That something, it turns out, is her finale, the glorious "Sandcastle Disco"; 2013 marks five years since that, and its parent album, came out. If she's got a few more like it hidden up her garish sleeves, some of us, at least, are all ears.

In the week that HMV goes into administration, and much is made of the endurance of smaller indie outlets (not to mention the corporate chain's guilt in killing off the ones we've lost), it's fittingly symbolic that Everything Everything, who on Monday played the last HMV instore in Manchester, should the next day shuttle south to booming Rough Trade East in London.

And, fittingly, the band are showing a growing ability to walk a tightrope between the indie world and the mainstream, and of fashioning hooks which barb their way under your epidermis.

Only a week ago, I gave their second album Arc a 7/10 review, a mark I would now like to rescind as it's already gained at least a point since. Some records do that. Some bands do that. What's becoming clearer and clearer about Everything Everything, hearing their chiming top-string motifs, their two-part harmonies and bubbling synths, is their desire to chop and mould pop's building blocks into new configurations. Even to the extent of bucking pop's rules by putting the ridiculously handsome one on bass.

The stuttering single "Cough Cough", with its looped "Yeah ... uh ... so ... wait a second" lyric, is a case in point, although, with their vocabulary of genuflections, Kalashnikovs and trilobites, there's also an intriguing depth when you scratch underneath the surface.

Everything Everything are, essentially, the band Alt-J think they are (although Jonathan Higgs could, in all honesty, do with ratcheting down the falsetto a little, if only to reduce that unfortunate comparison). And, in its launch week, Arc defied the landscape of record racks and air ducts to sound bigger and brighter than it did even seven days ago. It's big, bright, unabashed and unashamed pop. Just not as we know it.

Critic's Choice

The X Factor Live tour will begin at Manchester Arena (Sat), assuming James Arthur can keep it in his trousers long enough to go onstage. Meanwhile, Nineties comeback band Spin Doctors challenge you to name more than one song by them at HMV Picture House, Edinburgh (Wed); Eric's Club, Liverpool (Thu); Brudenell Social Club, Leeds (Fri); The Factory, Porth (Sat); and The Fleece, Bristol (Sun).